Search Results for author: Amir-Massoud Farahmand

Found 32 papers, 7 papers with code

Dissecting Deep RL with High Update Ratios: Combatting Value Overestimation and Divergence

no code implementations9 Mar 2024 Marcel Hussing, Claas Voelcker, Igor Gilitschenski, Amir-Massoud Farahmand, Eric Eaton

We show that deep reinforcement learning can maintain its ability to learn without resetting network parameters in settings where the number of gradient updates greatly exceeds the number of environment samples.

Improving Adversarial Transferability via Model Alignment

no code implementations30 Nov 2023 Avery Ma, Amir-Massoud Farahmand, Yangchen Pan, Philip Torr, Jindong Gu

During the alignment process, the parameters of the source model are fine-tuned to minimize an alignment loss.

Maximum Entropy Model Correction in Reinforcement Learning

no code implementations29 Nov 2023 Amin Rakhsha, Mete Kemertas, Mohammad Ghavamzadeh, Amir-Massoud Farahmand

We propose and theoretically analyze an approach for planning with an approximate model in reinforcement learning that can reduce the adverse impact of model error.

Density Estimation reinforcement-learning

Understanding the robustness difference between stochastic gradient descent and adaptive gradient methods

1 code implementation13 Aug 2023 Avery Ma, Yangchen Pan, Amir-Massoud Farahmand

In the context of deep learning, our experiments show that SGD-trained neural networks have smaller Lipschitz constants, explaining the better robustness to input perturbations than those trained with adaptive gradient methods.

Efficient and Accurate Optimal Transport with Mirror Descent and Conjugate Gradients

1 code implementation17 Jul 2023 Mete Kemertas, Allan D. Jepson, Amir-Massoud Farahmand

We design a novel algorithm for optimal transport by drawing from the entropic optimal transport, mirror descent and conjugate gradients literatures.

Benchmarking

$λ$-models: Effective Decision-Aware Reinforcement Learning with Latent Models

no code implementations30 Jun 2023 Claas A Voelcker, Arash Ahmadian, Romina Abachi, Igor Gilitschenski, Amir-Massoud Farahmand

The idea of decision-aware model learning, that models should be accurate where it matters for decision-making, has gained prominence in model-based reinforcement learning.

Continuous Control Decision Making +2

Operator Splitting Value Iteration

no code implementations25 Nov 2022 Amin Rakhsha, Andrew Wang, Mohammad Ghavamzadeh, Amir-Massoud Farahmand

We introduce new planning and reinforcement learning algorithms for discounted MDPs that utilize an approximate model of the environment to accelerate the convergence of the value function.

reinforcement-learning Reinforcement Learning (RL)

Deep Reinforcement Learning for Online Control of Stochastic Partial Differential Equations

no code implementations NeurIPS Workshop DLDE 2021 Erfan Pirmorad, Faraz Khoshbakhtian, Farnam Mansouri, Amir-Massoud Farahmand

In many areas, such as the physical sciences, life sciences, and finance, control approaches are used to achieve a desired goal in complex dynamical systems governed by differential equations.

reinforcement-learning Reinforcement Learning (RL)

Beyond Prioritized Replay: Sampling States in Model-Based RL via Simulated Priorities

1 code implementation28 Sep 2020 Jincheng Mei, Yangchen Pan, Martha White, Amir-Massoud Farahmand, Hengshuai Yao

The prioritized Experience Replay (ER) method has attracted great attention; however, there is little theoretical understanding of such prioritization strategy and why they help.

Understanding and Mitigating the Limitations of Prioritized Experience Replay

2 code implementations19 Jul 2020 Yangchen Pan, Jincheng Mei, Amir-Massoud Farahmand, Martha White, Hengshuai Yao, Mohsen Rohani, Jun Luo

Prioritized Experience Replay (ER) has been empirically shown to improve sample efficiency across many domains and attracted great attention; however, there is little theoretical understanding of why such prioritized sampling helps and its limitations.

Autonomous Driving Continuous Control +1

SOAR: Second-Order Adversarial Regularization

no code implementations4 Apr 2020 Avery Ma, Fartash Faghri, Nicolas Papernot, Amir-Massoud Farahmand

Adversarial training is a common approach to improving the robustness of deep neural networks against adversarial examples.

Adversarial Robustness

Policy-Aware Model Learning for Policy Gradient Methods

1 code implementation28 Feb 2020 Romina Abachi, Mohammad Ghavamzadeh, Amir-Massoud Farahmand

This is in contrast to conventional model learning approaches, such as those based on maximum likelihood estimate, that learn a predictive model of the environment without explicitly considering the interaction of the model and the planner.

Model-based Reinforcement Learning Policy Gradient Methods

Frequency-based Search-control in Dyna

no code implementations ICLR 2020 Yangchen Pan, Jincheng Mei, Amir-Massoud Farahmand

This suggests a search-control strategy: we should use states from high frequency regions of the value function to query the model to acquire more samples.

Model-based Reinforcement Learning

An implicit function learning approach for parametric modal regression

no code implementations NeurIPS 2020 Yangchen Pan, Ehsan Imani, Martha White, Amir-Massoud Farahmand

We empirically demonstrate on several synthetic problems that our method (i) can learn multi-valued functions and produce the conditional modes, (ii) scales well to high-dimensional inputs, and (iii) can even be more effective for certain uni-modal problems, particularly for high-frequency functions.

regression

Value Function in Frequency Domain and the Characteristic Value Iteration Algorithm

no code implementations NeurIPS 2019 Amir-Massoud Farahmand

We call the new representation Characteristic Value Function (CVF), which can be interpreted as the frequency domain representation of the probability distribution of returns.

Hill Climbing on Value Estimates for Search-control in Dyna

no code implementations18 Jun 2019 Yangchen Pan, Hengshuai Yao, Amir-Massoud Farahmand, Martha White

In this work, we propose to generate such states by using the trajectory obtained from Hill Climbing (HC) the current estimate of the value function.

Model-based Reinforcement Learning Reinforcement Learning (RL)

Improving Skin Condition Classification with a Visual Symptom Checker Trained using Reinforcement Learning

no code implementations8 Mar 2019 Mohamed Akrout, Amir-Massoud Farahmand, Tory Jarmain, Latif Abid

Moreover, the increased accuracy is up to 10% compared to the approach that uses the visual information provided by CNN along with a conventional decision tree-based QA system.

General Classification Question Answering +2

Iterative Value-Aware Model Learning

no code implementations NeurIPS 2018 Amir-Massoud Farahmand

This paper introduces a model-based reinforcement learning (MBRL) framework that incorporates the underlying decision problem in learning the transition model of the environment.

Model-based Reinforcement Learning

Improving Skin Condition Classification with a Question Answering Model

no code implementations15 Nov 2018 Mohamed Akrout, Amir-Massoud Farahmand, Tory Jarmain

We present a skin condition classification methodology based on a sequential pipeline of a pre-trained Convolutional Neural Network (CNN) and a Question Answering (QA) model.

Classification General Classification +1

Random Projection Filter Bank for Time Series Data

no code implementations NeurIPS 2017 Amir-Massoud Farahmand, Sepideh Pourazarm, Daniel Nikovski

Different filters in RPFB extract different aspects of the time series, and together they provide a reasonably good summary of the time series.

Time Series Time Series Prediction

Attentional Network for Visual Object Detection

no code implementations6 Feb 2017 Kota Hara, Ming-Yu Liu, Oncel Tuzel, Amir-Massoud Farahmand

We propose augmenting deep neural networks with an attention mechanism for the visual object detection task.

Object object-detection +1

Classification-based Approximate Policy Iteration: Experiments and Extended Discussions

no code implementations2 Jul 2014 Amir-Massoud Farahmand, Doina Precup, André M. S. Barreto, Mohammad Ghavamzadeh

We introduce a general classification-based approximate policy iteration (CAPI) framework, which encompasses a large class of algorithms that can exploit regularities of both the value function and the policy space, depending on what is advantageous.

Classification General Classification

Action-Gap Phenomenon in Reinforcement Learning

no code implementations NeurIPS 2011 Amir-Massoud Farahmand

Many practitioners of reinforcement learning problems have observed that oftentimes the performance of the agent reaches very close to the optimal performance even though the estimated (action-)value function is still far from the optimal one.

reinforcement-learning Reinforcement Learning (RL)

Error Propagation for Approximate Policy and Value Iteration

no code implementations NeurIPS 2010 Amir-Massoud Farahmand, Csaba Szepesvári, Rémi Munos

We address the question of how the approximation error/Bellman residual at each iteration of the Approximate Policy/Value Iteration algorithms influences the quality of the resulted policy.

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